The present invention relates to a communication system and associated method for improving its quality of service, and particularly to a communication system and an associated method when there is a jointly used transmission medium.
Such a communication system and associated method are disclosed in WO 99/11081 A, where a number of subscriber stations in a mobile radio network are provided and can each perform either a master function or a slave function. The functions are distributed over the subscriber stations by evaluating quality-of-service measurements in the mobile radio system.
A significant escalation in, by way of example, cordless communication systems means that, in the future, the case will frequently arise that two or more independent communication systems use the same transmission medium, such as frequency bands. This can result in interference or even in one or more of these communication systems failing.
When using, by way of example, two communication systems which operate on the basis of the same transmission method or transmission format (e.g., DECT), the standards stipulate methods for avoiding such interference. These conventional methods are known, by way of example, by the term dynamic channel allocation. This allows interference and collisions between independent communication systems to be prevented to a certain degree.
Particularly when using independent communication systems which operate on the basis of different transmission methods and use a common transmission medium, such as Bluetooth, HomeRF, Powerline Communications (PLC), etc., interference which is sometimes considerable arises which can even result in one type of communication system failing. With a jointly used transmission medium, such as the ISM frequency band (Industrial, Scientific, Medical), in which a large number of communication systems can operate up to a predetermined transmission level, there therefore can be a high level of interference or incomplete utilization of the resources of the jointly used transmission medium. To be more precise, by way of example, a communication system can no longer work, or can work only inadequately, in a jointly used transmission medium in which, by way of example, microwaves, radio remote controls, babyphones and the like are also operating.
The present invention is, therefore, directed toward a communication system and associated method for improving its quality of service which are simple and expensive to achieve.